1. Field of the Invention
The present invention relates generally to optical disk handling devices, and more particularly, but not by way of limitation, to an apparatus for separating a single optical disk from the bottom of a stack of optical disks for the purpose of labeling, packaging, duplicating, inspecting, or performing other processing steps on the separated optical disk.
2. Brief Description of the Related Art
An optical disk is a storage medium that holds information in the form of a pattern of marks on a platter. An optical-disk drive in turn reads, erases, or writes data on the disk with a laser beam. Examples of optical disks include CD-Audio, CD-Video, CD-ROM, CD-R, WORM, DVD, and DVD-ROM. The use of optical disks for storing data has evolved rapidly in recent years and continues to evolve in that optical disks are able to store a large amount of information in a small space and optical disks are extremely durable with some types of optical disks expected to last many decades.
Optical disks are generally fabricated of a clear plastic base impressed on one side thereof with information. A reflective layer of aluminum, gold, or the like is then applied to the base and covered with a lacquer coating for protection. During the final stages of production, the disk is printed with graphics, inspected, and packaged.
In order to meet the high demand for optical disks, large numbers of optical disks must be rapidly produced. Therefore, devices have been designed to hold such disks in bulk and to individually feed the disks to various pieces of production equipment. Such devices typically include a robotic swing arm provided with a vacuum system which removes the optical disk positioned on the top of a stack of disks, delivers the removed disk to the processing equipment, and then returns to remove the next disk. While these types of devices have achieved varying degrees of success, their inherent complexity results in a device that is expensive to manufacture and requires a high degree of attention to maintain. In addition, by removing the disk from the top of the stack, operation of these devices must be periodically interrupted to replenish the supply of disks, or the device must be provided with a carousel mechanism adapted to hold multiple stacks of optical disks. To this end, it would be desirable to be able to separate the disk located at the bottom of the stack whereby one stack could be continually replenished without having to halt production.
Several devices have previously been proposed for removing a disk-like object from the bottom of a stack. One such device is disclosed in U.S. Pat. No. 5,050,023, issued to H. D. Ashby, the present inventor. The Ashby '023 patent discloses a mechanism for separating a floppy diskette from the bottom of a stack of floppy diskettes. The mechanism includes a pair of opposing feed subassemblies which function to position a pair of opposing, wedgeshaped ribs between the bottom diskette and the adjacent diskette so as to support the stack while allowing the bottom diskette to be released from the stack.
U.S. Pat. No. 5,611,436, issued to H. D. Ashby, discloses the use of a similar mechanism for separating a PC card from the bottom of a stack of PC cards.
While such mechanisms have successfully met the need for rapid and reliable handling of diskettes and PC cards, problems are encountered when attempting to employ the same mechanism for separating optical disks. It has been found that these problems stem from the structural differences between diskettes and PC cards relative to an optical disk. In addition to the obvious difference that diskettes and PC cards are square and rectangular in shape while an optical disk is circularly shaped, the outer peripheral edges of the jackets of diskettes and PC cards are slightly rounded. This results in a peripheral notch or indentation being formed between each diskette or PC card when the diskettes and PC cards are aligned in a stack. The formation of this notch provides an accessible space into which a wedge member can be easily inserted to separate adjacent diskettes or PC cards. In contrast, the outer peripheral edge of the plastic base of an optical disk is substantially squared relative to the opposing planar faces of the base. As such, when optical disks are arranged in a stack with the outer peripheral edges aligned, there is no readily accessible space provided between the optical disks into which a wedge device can be reliably inserted to separate adjacent optical disks.
To this end, a need exists for an apparatus which can separate an optical disk from the bottom of a stack of optical disks without affecting the integrity of the disk, and which has a minimum of moving parts to provide low cost maintenance while reliably handling large numbers of optical disks. It is to such an apparatus that the present invention is directed.